Method of manufacturing rivets



Feb. 11, '1936. Q HUCK 2,030,171

METHOD OF MANUFACTURING RIVETS l original Filed April 12, 1932 fw? iE-/6 n AA@ IN VENTOR. 0 d'5 C'. #af/k BY IgM',

I w y ATTORNEYS.

Patented Feb. 1l, 1936 UNITED -STATlazs METHOD F MANUFACTURING RIVETSLouis C. Huck, Detroit, Mich., assignor to Hnxon Holding Corporation, acorporation of Michigall Original application April 12, 1932, Serial No.604,759. Divided and this application January 24, 1935, Serial No. 3,262

The invention relates to rivets and it has particular relation to amethod of manufacturing rivets. Also,l it constitutes a division of thatembodied in my co-pendlng application for patent, Serial No. 604,759,led April 12, 1932 and entitled Rivet and method of manufacturing same.

In general the invention relates to a rivet comprising a tubular femalemember and a male or shank member extending through the female lo memberand having a head at one end for engagement with one end of said tubularmember.

- That end of the male or shank member opposite the head, projectsvbeyond the opposite end of the tubular member and iserves as a grippingmeans l5 during the rivet setting operation, when'such end of the malemember is pulled and the reactionaryforce is applied against theadjacent 'end of the female member. This assembly Vis inserted throughopenings in a structure to be riveted and during the rivet settingoperation, the head on the male or shank member applies an axiallycompressive force to the adjacent end of the female member, which isopposed to the above mentioned reactionary force applied to the oppositeend of the female member, and as a result the tubular member between thestructure being riveted and the end thereof abutting the head of themale member, may be bulbed outwardly to form a head against thestructure. A similar head might be formed at the opposite side of thestrueture, but preferably a head will initially be formed at this end ofthe member and the reactionary force to the pull on the shank will beapplied through such head and ordinarily against the 35 structure beingriveted. In rivet setting in this manner it is quite important that theend of the female member abutting the head on the male member bereinforced against bursting so as to prevent the head on the latter frommoving into or through the female member.

One object of the invention is to provide a method of manufacturing e.rivet comprising a female, tubular member, and a shank or male memberextending therethrough, in which the end of the female member to bereinforced against bursting, is so manipulated or treated duringassembly of the male and female members that such reinforcement iseffected eiilciently and inexpensively.

Another object of the invention is to provide a' method of manufacturinga female rivet member, in which the end of the latter is reinforcedagainst bursting by so treating the material of 56 which it is composedthat its inherent strength y is increased with respect to the materialforming the remainder of the member.

Other objects of the invention will be apparent from the followingdescription taken in conjunction with the drawing and from theclaimshere- 5 inafter set forth.

For a better understanding of the invention, reference may be had to theaccompanying drawingforming a part oi' the specication, wherein:

Figure 1 is a longitudinal cross-sectional view 10 of a rivet assemblyconstructed according to one form of the invention, illustrating themanner inwhich the female and male members are constructed prior to andafter the initial assembling operation; 15

Figure 2 is asimilar view, illustrating how an enlarged lend portion ofthe female member is radially contracted into a. groove in the end ofthe male member;

Figure 3 illustrates on a larger scale, the rivet 20 shown by Figure 2,as utilized for riveting a structure;

Figure 4 is a fragmentary cross-sectional view. illustrating a femalemember constructed according to another form of the invention, prior to25 assembling it with the male member;

Figure 5 illustrates the female member shown by Figure 4, after an kendthereof has been flared out slightly either prior to or during assemblythereof with the male member; 3o

Figure -6 is a cross-sectional view illustrating a male member such asthat shown by Figure 1, assembled with the female member shown by Figure5, after the dared out end shown by Figure 5 is radially contracted intothe groove in 35 the male member;v

Figure 7 is a fragmentary cross-sectional view of a rivet which may beconstructed similarly to the construction illustrated by Fig. 6, butwhich. is of slightly different construction;

Figure 8 is a longitudinal cross-sectional view of a female member Whichmay initially be constructed similarly to the construction of a femalemember illustrated by Figure 1;

Figure 9 illustrates the manner in which the 45 slightly enlarged end ofthe female member is reduced in outer diameter without substantiallychanging its inner diameter, so as to strain harden the end portion ofthe female member for reinforcement purposes; Y l o@ Figure l0illustrates the female member constructed according to Figures 8 and 9,as assembled with a male member similar to that shown by Figure l, and

e il illustrates another form of the invention in which the femalemember has a groove in its outer surface adjacent the male member head.v

- Referring to Figure 1, the assembled rivet comprises a female memberIII of tubular character, having a tubular head II at one end, and abody portion I2 defined by a continuous annular wall of substantiallyuniform radial thickness member, and has a head I5 at one end forengaging the end face. of the collar or shoulder I3. The maximum outerdiameter of the head I5 preferably corresponds substantially to theouter diameter of the Abody portion I2, and an end portion of the headas indicated at I6 may be beveled to facilitate inserting the assemblyinto structural openings.

The male member adjacent the head I5 and f radially inward of the collarI3 is provided with an annular groove Il, and longitudinally spaced fromthis groove, it has an undercut or neck I3 which is located intermediatethe ends of the female member when the parts are initially assembled.'I'he male member also projects beyond the head II of the female memberand its projecting end portion Is provided with threads or grooves I9,for facilitating gripping thereof by jaws in a rivet setting machinewhich may, for example, be similar to that disclosed in the applicationfor patent of Louis C. Huck and Ralph A. Miller, Serial No. 560,289, ledAugust 31, 1931.

Preferably, that part of the male member between the groove II and theundercut or neck I8 will initially have atleast a slight press t in thebody I2 of the female member and that part of the male member betweenthe threads or grooves I9 and such undercut I8 preferably will be ofslightly smaller outer diameter to facilitate assembling the members.When the parts are thus assembled as shown in Figure 1, suitable meanssuch as a shrinking or swedging die, may be employed for radiallycompressing or contracting the collar or shoulder I3 into the annulargroove I1 in the male member.

As shown in Figure 1, a shrinking die is employed which may comprisesegments 20 and 20 adapted to be bolted to platens as indicated at 2 IOne platen may be movable with respect to the other so that the segmentsmay be set about the female rivet member. Such segments havesemi-cylindrical portions 22' for substantially fitting the body portionI2 although not binding thereon, and conical or tapered portions 23' tothe right thereof. When the rivet assembly lis moved to the left throughthe die, as by pulling the male member at the left end or pushing theright end thereof, the conical portions gradually force the collar onthe female member into the groove I1 in the male member, and finally thesemi-cylindrical parts of the die render the collar portionsubstantially cylindrical and of approxim`ately the same outer diameteras that of the body I2. Preferably the excess of metal in the collarwill llthe groove I1, but if there should be more than this amount ofmetal, the die would shear or extrude it past the end of the femalemember. The assembly as thus manufactured is illustrated in Figure 2. Itshould be appreciated that such collar or shoulder as a result of itsgreater radial thickness, Will have greater resistance to bursting andhence will more strongly resist any movement of the head I5 of the malemember through the female member when the threaded end I9 of such malemember is pulled while applying the reactionary force against the head II of the female member'. While the collar I3 as shown in Figure 1, wouldaccomplish this purpose, its outer diameter is such that it would beimpossible to insert the assembly through openings in a structure to beriveted by inserting the head I5 of the male member first, particularlyif there were only slight clearance between the outer diameter ofthe'body I2 of the female member and the openings in the structure andnormally this would be the case. Accordingly by swedging or radiallycontracting the collar I3 into the groove Il in the male member, theouter diameter of such collar may be reduced until it substantiallycorresponds to the outer diameter of the body portion I2, as clearlyshown by Figure 2, thereby permitting insertion of the assembly throughopenings in a structure to be riveted under the conditions described,While still obtaining the increased resistance to bursting at the end ofthe female member dened by the collar. Again it is evident that byradially contracting or swedging the collar I3 into the groove I1 in themale member the members are positively locked together against relativeaxial displacement, a1- though it should be understood that this lockingengagement will not prevent setting of the rivet but will be intendedprimarily to lock the parts together against displacement after therivet is set.

In setting the rivet, the assembly is inserted through openings instructural elements such as the plates 2| and 22 shown in Figure 3, bymaking the insertion from the left side of the struc-- ture, and then bypulling the threaded cnd I9 of the male member and applying thereactionary force to the head II of the female member, the head I5 onthe male member acting through the collar or shoulder I3 will causebulbing of the body portion I2 between the structural element 2| and thecollar, to form the bulbed head indicated at 23. During this operation,the shoulder or collar I3 vmay be axially compressed to some extent, butits end face will be maintained in contact with the end face of the headI5, and it will not twist about any circumferential axis, at least toany appreciable extent, during formation'of the bulbed h ead. It mightbe added that the dimensions of the male and female members, andparticularly the dimensions of the body I2, are such that initially andprior to forming of the bulb 23, the body I2 will be upset or axiallycompressed suiciently to fill any space between body and the sides ofthe openings in the plates, as Well as any space between the members insuch openings. After the head 23 is formed, tension on the male memberwill cause it to break at the base of the undercut or groove I8, andnormally this undercut will be so located thatthe break will occursubstantially at the outer end of the head I I on the female member sothat the broken end of the male member still in the female member willconstitute substantially acontinuation and iiush'part of the head I I.This line of rupture is indicated at 24 in Figure 3.

The dimensions of and materials in the male and female members, andparticularly the dimensions of the body I2 of such female member, maycorrespond to dimensions and materials set forth with respect to themale and female members in my co-pending application for patent, SerialNo. 599,868, led March 19, 1932. 'I'his type of construction insuresupsetting of the body I2 in the structural openings to fill the latterand thereby obtain a. tight rivet, and formation of the bulb 23 in thepreferred or globular manner as partioularly described in suchco-pending application for patent.

In the construction shown by Figure 4, the female member issubstantially identical to that disclosed in Figure 1 with the exceptionthat initially it is provided with a collar or annular shoulder 26 whichhas an outer diameter substantially corresponding to the other diameterof the body I2, but whose' inner diameter is reduced to provide thegreater radial thickness of the collar. After this construction isformed, the collar portion and adjacent end of the body I2 are outwardlyared as shown in Figure 5, so that the flared portion will have itssmallest inner diameter not smaller than the largest outer diameter ofthe male member body to be inserted. This flaring out may beaccomplished by a suitable tool or pin having a conical, enlargedportion to be inserted through the female member. As shown, theconstruction permits inserting a male member such as that shown byFigure l thereinto, until the head I2 on the male member substantiallyengages the end of the collar 26. Then by means of a suitable shrinkingdie or swedging die asshown in Figure 1, the collar or shoulder 26` maybe contracted radially into the groove I'i in such male member. Theresulting assembly is quite similar in appearance to that shown byFigure 1 but it will be appreciated that the collar 26 has beencontracted in the groove in the male member by a different treatment ofthe metal therein.

vIn the'construction shown by Figure "I, an arrangement similar to thatshown by Figure 6 is provided, with the exception that the end face ofthe collar 26 preferably is concaved or angled slightly as indicated at2l with respect to the axis of the member so that as finally assembledthe end face of the head I of the male member substantially contactswith the end face of the collar only along its outer margin as indicatedat 28. This facilitates obtaining greater stressing of the outer fibersof the body I2 with respect to stressing of .the inner bers thereofduring the rivet setting operation, and such difference of ber stress isinstrumental in locating the portion of body I2 of greatest diameterduring initial bulbing nearer to,the structure being riveted than to thecollar. It should be evident that the end face of the collar might 'beradial as shown in' end face of the collar would tend to align itselfwith the surface on the head of the male member and during subsequentsetting of the rivet, the angularlty of the contacting faces-on thecollar and male member head would tend also to direct may beinstrumental in locating the portion of body I2 of greatest diameterduring initial bulbing, nearer to the structure than-to the collar.

In the construction shown by Figures 8, 9 and 10, the body I2 of thefemale member initially this manner the inherent strength of resistanceto bursting of the end of the. female member is increased. It will benoted that this strain hardening increases fromthe beginning 35 of thetaper BIBv to the right end of the female member, as shown by crosshatching in Figure 10. Normally, the beginning of the strain hardenedportion may define the adjacent end of the bulbing portion of body I2,and accordingly by varying the length of the collar, and hence thestrain hardened portion, the end of the bulbing portion adjacent theretomay be varied in location. 'I'his type of female member might beconstructed by strain hardening a solid element having the taperedshoulder or collar, and then drilling therethrough to make the membertubular. Instead of so treating the material in the collar in thismanner, the female member might instead of having a collar of increasedradial thickness, have an end portion corresponding in inner and outerdiameter to the body portion I2 and then such end might be heat treatedto increase its bursting may be employed to vary the location of theright end of the bulbing body portion similarly vto the manner describedin conjunction with the strain hardening shown by Figure 10. When afemale` member of either type is assembled with a male strength. Thelength of the heat treated portion member as 'shown by Figure 10, andthe rivet is set the female member may be compressed axially to cause anow of metal into the groove Il, suicient -to lock the members againstrelative axial movement after the rivet is set.

In the'construction shown by Fig. 11, the female member is similar tothat shown by Fig. 2 but has a groove 36 in its outer surface adjacenttothe left end of the collar to further facilitate preventingcircumferential twisting of the collar during setting of the rivet, andmaintaining the end face of the collar parallel to the adjacentl face onthe head ofthe male member. This groove might also be employed in theother constructions shown.

It has been stated in conjunction with Figs. 1 to 3 inclusive that thematerials in and dimensions of the female and male members mightcorrespond to those materials and dimensions set forth in my co-pendingapplication for patent referred to above. Such relation of materials anddimensionsjnay also apply to the remaining iigures. Particularly, thewall thickness of the body portion I2 is so proportioned to the outerdiameter thereof that upsetting of the metal thereof in the structuralopenings should occur to fill them tightly prior to bulbing, and also asstated in my co-pending application for patent, the bulblin its initialstage of bulbing should be globular or have substantially uniform radiusof curvature in axial cross section.

In certain of the claims the term upsetting where used to indicatetreatment of the:v metal .in the tubular member, should not beunderstood to have any strict technical definition. A flow of movementof the metal to obtain an increased resistance to bursting is generallyintended where the term upsetting is employed.

In any of the constructions described and illustrated the end of thefemale member abutting the male member head is strongly reinforcedagainst bursting and the increased bursting strength is eiected prior toany phase of the rivet setting operation.. It is also apparent thatrivet constructions have been provided in which the male and femalemembers are positively locked against axial displacement other than thatnecessary for setting the rivet by the same means that increases thebursting strength of the end of the female member. It is also apparentthat novel methods have been' provided for manufacturing rivetconstructions to obtain female members with increased bursting strengthat the ends thereof, to be engaged by the male member head and that suchmethods of manufacture involve a minimum number of operations andrelatively little expense.

Although more than one form of the invention has been described andillustrated in detail it will be apparent'to those skilled in the artthat various modifications may be made without departing from the scopeof the appended claims.

I claim:A

l. The method of manufacturing a rivet, which comprises forming atubular member, forming a shank for extending through the tubularmember, forming an annular surface recess in a part of one member,assembling the parts, and then rolling a part of r such member nothaving said recess, into the latter, to lock parts of the membetogether.

2. The method of manufacturing a rivet, comprising forming a tubularmember with an end portion o'f enlarged radial thickness, and thenradially compressing the enlarged portion to increase its strengthcharacteristics.

3. The method of manufacturing a rivet, comprising forming a tubularmember with an end portion of enlarged radial thickness but with aninner diameter substantially equal tosthe inner diameter of theremainder of the member, forming a shank member with a head for engagingsuch enlarged'- end of the tubular member and with a groove adjacentthereto, extending the shank through the tubular member and then forcingthe enlarged portion of the tubular member, radially into the groove.

4.-- The method of manufacturing a rivet which comprises forming atubular member, forming an i end portion of greater outer diameter onsuch member, and then radially contracting the end portion until itsouter diameter is not greater than the outer diameter of the memberintermediate its ends.

5. The method of manufacturing a rivet which comprises forming a tubularmember, with an end portion of greater outer diameter than the outerdiameter of an intermediate portion of the member, forming a shank forextending through the member, forming a recess in the shank, associatingthe parts, and contracting such larger end portion of the tubular memberinto such recess.-

6. The method of manufacturing a rivet which comprises forming a tubularmember with an end portion of greater radial thickness, forming a shankfor extending through the tubular-mem ber, forming a groove in the outersurface `of such member, assembling the parts, and then radiallycontracting such end portion of the tubular member into the groove.

7. The method of manufacturing a rivet which comprlsesforming a tubularmember with an end portion of smallerv inside diameter, forming a shankwith a. recess, extendingthe shank through the tubular member and thusenlarging the inside diameter of the end portion of the tubular member,and then radially contracting such end portion into the recess.

8. The method of manufacturing a rivet which comprises forming a metaltubular member, and increasing the bursting strength of one end of themember by reducing its outer diameter through an inherent movement orflow of the metal.

9. 'Ihe method of manufacturing a tubular rivet member which comprisesproviding a solid pin element, forming a head on one end of the elementand upsetting an end sector at the other end of the element to strainharden it and increase its resistance to radial expansion, and thenforming a central opening longitudinally in the element.

10. The method of manufacturing a tubular rivet member which comprisesproviding an elongated ele'ment with a longitudinal and central openingand a wallportion of increased radial thickness, and then reducing thethickness of such portion by upsetting and strain hardening the metal.

11. The method of manufacturing a tubular rivet member which comprisesforming a metal tubular element with a head on one end, and increasingthe bursting strength of an end sector at the opposite-end of thetubular member by strain hardening the metal in such sector, so as topro- 4 vide a member which has less resistance to ex-\

